I'm scared about meeting Amanda Donohoe. The last time she talked to an Observer journalist, six years ago, she was sensationally bolshy and rude. 'What a stupid question!' she said when asked something innocuous about her background, and 'Do you know, I am really bored with this conversation,' and 'How much do you earn, anyway? How can you live on that?'

Because she is such a bugger to spend time with, constantly ticking off hacks and telling them how to do their jobs, Donohoe, unlike so many of her colleagues in the acting fraternity, has always made for great copy, because it would seem that she has never really felt the need to make herself likeable.

Anyway, here is The Observer, greedy for punishment. Things are looking promising. Amanda is late: 10, 15 minutes, half an hour. I'm told that she's on her way from the hairdresser's, and then someone else says that of course she should be getting out of rehearsals any moment now.

Because Amanda is about to inherit Mrs Robinson's famous stockings (and that nudie scene) from Jerry Hall, I'm sitting in the Soho offices of The Graduate 's co-producer Sacha Brookes, and he is explaining that casting Mrs R is just a matter of closing one's eyes and sticking a pin in a personal fantasy wishlist, and the photographer is getting into it, suggesting Greta Scacchi and 'who else did I fancy in the early Eighties?'

It is immediately apparent - and actually, I won't pretend to be disappointed about this - that she is in a very good mood today, thespily throwing herself at the feet of one of Mr Brookes's assistants who provides a packet of cigarettes, and letting rip with her sexy, smoke-edged laugh, not least when she wants to signpost a remark as not entirely serious, which, to my surprise, is fairly often.

Is this her fourth or fifth window of opportunity? Fact is, Amanda, the daughter of two north London antique dealers, first squared up to fame as a 15-year-old when she started dating Adam Ant, then on the very threshold of pop stardom. After training at Central, she reappeared in Nic Roeg's notorious Castaway (1986) which cast her opposite Oliver Reed and obliged her to spend most of the shoot in the buff.

Her costumes stayed minimal in the follow-up roles (several Ken Russell flicks), and somehow it was not a surprise when she departed for the States, where she did a two-year (1990-92) stint as a gay attorney on LA Law. Her comparatively recent relaunch as a stage actress (Miss Julie, Snoo Wilson's HRH) has been well received by the critics.

Every evolutionary step has been logged by interviewers and, as she has never been one to take any prisoners (probably one reason why the key roles never came her way after she moved to Hollywood), those earlier incarnations haunt her still. She mentions her age, 38, twice during the interview, defying the conventions of her profession; but then again, you might do the same if you were always being asked to comment on some off-the-cuff remark you smacked towards the boundary 20 years ago.

'My first love affair was on the front page of every bloody newspaper. My first betrayal on the front page. It was very odd, to grow up like that,' says Donohoe, leaning back into a scarlet sofa and tilting a big glass of red wine towards her. 'You should be careful what you wish for. I very much wanted that sort of exposure, but I had no idea what the cost of it would be. I just wanted to be popular, famous and successful at what I did. I didn't really think of the consequences at all. That's how you start.'

And because she started so young, and wore so few clothes on screen, and was always articulate and sometimes reckless in interviews, she was all over the tabloids: a pushmepullyou scenario. 'The press condemned me for my rebelliousness, but they wanted it, too. So I was given very mixed messages about what I was doing. I was encouraged on one hand to be vocal, and then told that I talked too much, or that I talked rubbish. I didn't know what was going on. It made me very untrusting. I don't have a lot of trust.'

The funny thing is that today she is a very generous interviewee - very trusting, really. When I ask if it's true that she has decided to leave Los Angeles, where she has lived since 1989, and come back to London for good, she confirms it: LA, for all the sunshine, or perhaps because of it, 'is like an anaesthetic: it numbs you. I bought into that, sat on my arse, and that seemed to be enough for a while.' It was, until she turned 35.

The only recent strong role for an 'older woman' that she can think of - she really went after it - was that of presidential press secretary C.J. Cregg in TV's The West Wing, bagged by Allison Janney. 'No matter who you are, Elizabeth Taylor, Michelle Pfeiffer, it's over at a certain age. And then you either get bitter, or you move on. I've been very lucky because I've had the English stage to move back to.' She's always kept one toe on it, doing theatre in London and Manchester between screen outings in Liar Liar and The Madness of King George. Now her ambition is to pull off a Judi Dench, a Francesca Annis or a Helen Mirren.

But there was another fundamental problem with LA. 'I also found it very difficult to find American men that I found interesting for more than a couple of months, and that was really getting me down. For all my complaining I do love England, and I do love Englishmen. It's only when you've lived abroad and dealt with other cultures, and the men in them, that you realise that actually English blokes are all right. They really are.'

Over the past few years, Donohoe, whose exes include the filmmaker Nick Broomfield, has taken a gloomier line on relationships. In 1997, announcing that the time had come for her to try the single life, she told the Sunday Times: 'I had one big lie too many.' So, why the change of heart? 'I had a couple of relationships with American men, but they didn't last very long.

'Lovely, lovely charming people, but I'd make a joke and they wouldn't understand it. That's when the warning signals started going off. And they were so goddamn polite - and if they're not goddamn polite, they're not very inventively rude, either. And then they stab you in the back with a big smile. Here people pretty much say what's on their mind. And on the whole, I'd rather see the knife coming at me.'

A little indignant that chaps her own age seem preoccupied with younger women, she is chuffed, if not entirely consoled, that the next generation still seem interested. 'It's not that I'm chasing younger men; they're chasing me. And I say, "Darling, you know, you're gorgeous, but it would be cradle snatching."'

Her time as a singleton has been useful; she feels as if she has sorted herself out a bit. 'And now I think I'm quite ready. But I don't want another series of affairs. I want some kind of deeper, more permanent relationship. I don't mean marriage, I'm not looking for marriage. No, I'm looking for a companion. A person to share all sorts of interests...' and suddenly she cackles, witchily, 'as well as sex.'

Her peculiar sort of UHT fame has always got in the way of relationships. 'I'd never noticed this before until recently, perhaps I've been too self-absorbed. It's really funny - when you meet people, they have this slightly glazed, excited look about them. They're not looking at you or listening to you. They're looking at the celebrity - at the veneer, at their own fantasy, if you like. And that is so offputting, I can't even tell you.'

She's sure that when she first arrived in Hollywood, she wore the same expression, and it didn't make for interesting conversation then, either. 'That's why celebrities date celebrities. It's a shortcut to an intimacy. You've both been there, done that. That's daft, really. I mean, I don't want to date a celebrity. I want a person, a normal human being.' She leans towards my tape recorder. 'Is there anybody out there?'

So Amanda is letting down the drawbridge. Her parents have been the first to cross it. Having spent most of her life being rather dismissive of her mother and father and their sensible, middle-class approach to life, she is now making amends. When she went to the States, she slipped into the habit of only ringing home on feast days, so when friends who had lost their parents before making peace expressed regret: 'That was a bit of an eye-opener'.

The clincher came with the deaths of Diana and JFK Jr which - apparently for the first time - forced Amanda to accept the fact that she was not immortal. 'Life is short and unpredictable and I suppose it has taken me till 38 to grasp that.' There was a reconciliation, a few tears, an apology, and she has since discovered a maniacal curiosity about her Irish, Russian and Swiss family roots. 'It does help,' she says. 'It helps you to figure out where you're going, where you came from, who you might be.'

She's house-hunting at the moment, around north London, where she grew up. 'I have been incredibly undisciplined in my life. I've had a party, and now the party's over. Well, it's not that the party is over ,' she amends, hastily, 'but I'm not going to wake up with a hangover the next day.'

I do like the way she's going about it: rootling around in a box of Godiva chocolates she has spotted on the coffee table, lighting another fag, pouring some more wine. Let's not get carried away: Donohoe has not mellowed and, fingers crossed, never will. If she approves of something, she will say that it 'gives you a good kick up the arse'. Change is good. Unpredictability is good.

Perhaps this is a necessary quality in someone who has spent their life striking attitudes for the media, but there's a splendid defiance to her U-turns. In her late teens, she was forever tripping off on CND rallies.

Now she is proud to front the new recruitment commercials for the Royal Navy. Her position changed, she says, after Kosovo. 'I grew up. I'm certainly not for the nuclear bomb, and I don't give a damn about the politicians: they send young men and women to their deaths without batting an eyelid. But the fact is that these young men and women are brave enough to go out there, risking their lives for us, for peace, whatever that means, and I think that they deserve respect, attention and support.'

Do you know, I think Amanda Donohoe is terrific. She wears her heart on her sleeve, and a very healthy organ it is, too, even if it beats to a slightly erratic rhythm. She will defend every caprice - and she's a creature of them - to the hilt, at least until the wind changes. I've caught her on a good day, when she says she's hoping to find a decent chap, doesn't want children and is thrilled to be back in London, but I don't doubt that someone else, meeting her next week, would find her in a terrible strop, renouncing men, planning to adopt, and packing her bags for Paris.

Donohoe wants an interesting life, not an easy one, and this means that even the trivial can suddenly be transformed into the epic. Take any mundane activity: clothes-shopping in London, for instance. 'You walk into a shop,' she says, 'and it's like they're doing you a favour. This shop assistant said, "Nah, you can't take more than six pieces into the changing rooms," and I thought, "Do you want to give me any service at all, or shall I just fall to my knees and beg you to let me use the changing room?" I tried a few things on, finally found something to fit me and went to the cash desk, and then I thought, they really don't deserve my custom. So I said, "Do you know what? I've changed my mind. Bye-ee!" So now my pride is intact, but I have no trousers to wear. What's a girl to do?'